LExEn: Hyperthermophiles of the Hydrothermal Vent Subsurface and Their Environmental Tolerance

LExEn：热液喷口地下的超嗜热生物及其环境耐受性

• 批准号: 0085534
• 负责人: Andreas Teske
• 金额: $ 36.04万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2003-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0085534&HistoricalAwards=false
• 关键词: LExEn; Hyperthermophiles; Hydrothermal; Vent; Subsurface

LExEn: Hyperthermophiles of the Hydrothermal Vent Subsurface and Their Environmental ToleranceHyperthermophilic archaea, isolated from deep-sea hydrothermal vents, survive and grow under extreme heat, pressure, and most likely chemical toxicity. Their isolation and detection in hydrothermal vent effluents and in solids from undersea volcanic eruptions strongly suggest that they also occur in hot and anoxic subsurface environments. Their ability to survive or grow under extreme subsurface hydrothermal vent conditions (pH, sulfide, metals, temperature, and pressure) will show whether these organisms have potential as widespread and environmentally tolerant deep-subsurface inhabitants. With the exception of temperature, and to some degree pressure, many critical factors which determine growth and survival of vent hyperthermophiles under subsurface conditions have not been tested, preventing a realistic assessment of the occurrence range and environmental tolerance of these organisms.This project will test the hypothesis that hydrothermal vent archaea actually grow inthe hot, anaerobic and toxic hydrothermal vent subsurface, most likely along the flow paths of vent fluids through the porous or cavernous rock. Four hydrothermal vent hyperthermophilic archaea will be used for these experiments, the methanogen Methanococcus jannaschii, the heterotrophic sulfur reducers Thermococcus fumicolans, Pyrococcus sp. strain GB-D, and the sulfate reducer Archaeoglobus profundus. These archaea were selected as a cross-section of anaerobic, thermophilic metabolisms which are representative for hydrothermal vent archaeal populations, and have the physiological potential to withstand subsurface conditions. Most importantly, these genera have been isolated directly from ongoing undersea eruptions and vent megaplumes. We will systematically test the growth and the survival of these vent archaea under approximated in situ conditions: high hydrostatic pressure of mid-ocean ridge hydrothermal vents and their subsurface extensions; acidic pH; and high sulfide and metal concentrations. These factors will be tested individually, and together in ways that approximate the natural situation. The hypothesis that the synergistic effects of these stress factors on growth and survival of hydrothermal vent archaea in the subsurface environment will differ considerably from the effect of each factor alone will be tested by comparing single-factor and multi-factor experiments. An important feature which influences growth and survival is biofilm formation, only recently studied for archaea model systems. Since biofilm formation enhances the environmental tolerance of many bacteria, archaeal biofilms in hydrothermal vent and subsurface environments are likely to show increased tolerance to environmental stress factors. In other words, the most resistant organism of hydrothermal vents and the earth's subsurface biosphere may not be an archaeon, but an archaeal biofilm. These experiments aim at integrating several physical and chemical factors which together determine the tolerance limits of some of the most extreme life forms on earth.

Lexen：水热通风地下的过度疗法及其环境耐受性胸膜古细菌，从深海水热通风孔中分离出来，在极高的热量，压力，最可能的化学毒性下生存并生长。它们在水热排气废水和海底火山喷发的固体中的隔离和检测强烈表明它们也出现在热和缺氧的地下环境中。它们在极端地下的水热条件下生存或生长的能力（pH，硫化物，金属，温度和压力）将表明这些生物是否具有广泛和环境耐受性的深层表面居民的潜力。除了温度和一定程度的压力外，尚未测试在下表面条件下确定排气高疗的生长和生存的许多关键因素，从而阻止对这些生物的发生范围和环境耐受性进行现实评估，这将测试该项目的水热频率在热，anaeerobic confer Feltface confersal confer conterfacters contersy contrifacty contrys contery contery contersy contery contery contersy contersy contersy conty compty的可能性流频率为流动性的，大多数伴随着静态的水平，并且具有毒性的流动性。多孔或海绵状岩石。这些实验将使用四个水热过度嗜好古细菌，即Jannaschii甲烷基甲烷菌，异育硫硫酸硫酸富菌素烟雾菌，pyrococcus sp。菌株GB-D和硫酸盐还原剂古细菌profundus。这些古细菌被选为厌氧，嗜热代谢的横截面，这些代谢代表了水热通风古细菌种群，并具有承受地下条件的生理潜力。最重要的是，这些属已直接与正在进行的下划线爆发和通风型巨型群体中隔离。我们将系统地测试这些通风古细菌在近似情况下的生长和存活：中山脊的高静水压及其地下延伸；酸性pH；以及高硫化物和金属浓度。这些因素将单独测试，并以近似自然情况的方式进行测试。这些应力因素对地下环境中水热古细菌生长和存活的协同作用的假设将通过比较单因素和多因素实验来测试每个因素的效果。影响生长和生存的一个重要特征是生物膜的形成，直到最近才研究了古细菌模型系统。由于生物膜的形成增强了许多细菌的环境耐受性，因此水热和地下环境中的古细菌生物膜可能显示出对环境应力因素的耐受性的提高。换句话说，水热通风孔和地球地下生物圈的最具耐药性可能不是古老的生物膜，而是古细菌生物膜。这些实验旨在整合几种物理和化学因子，共同决定了地球上某些最极端生命的耐受性极限。